1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver core for serial ports
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 * Copyright 1999 ARM Limited
8 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/kernel.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/device.h>
24 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
25 #include <linux/serial_core.h>
26 #include <linux/sysrq.h>
27 #include <linux/delay.h>
28 #include <linux/mutex.h>
29 #include <linux/math64.h>
30 #include <linux/security.h>
32 #include <linux/irq.h>
33 #include <linux/uaccess.h>
35 #include "serial_base.h"
38 * This is used to lock changes in serial line configuration.
40 static DEFINE_MUTEX(port_mutex);
43 * lockdep: port->lock is initialized in two places, but we
44 * want only one lock-class:
46 static struct lock_class_key port_lock_key;
48 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
51 * Max time with active RTS before/after data is sent.
53 #define RS485_MAX_RTS_DELAY 100 /* msecs */
55 static void uart_change_pm(struct uart_state *state,
56 enum uart_pm_state pm_state);
58 static void uart_port_shutdown(struct tty_port *port);
60 static int uart_dcd_enabled(struct uart_port *uport)
62 return !!(uport->status & UPSTAT_DCD_ENABLE);
65 static inline struct uart_port *uart_port_ref(struct uart_state *state)
67 if (atomic_add_unless(&state->refcount, 1, 0))
68 return state->uart_port;
72 static inline void uart_port_deref(struct uart_port *uport)
74 if (atomic_dec_and_test(&uport->state->refcount))
75 wake_up(&uport->state->remove_wait);
78 #define uart_port_lock(state, flags) \
80 struct uart_port *__uport = uart_port_ref(state); \
82 spin_lock_irqsave(&__uport->lock, flags); \
86 #define uart_port_unlock(uport, flags) \
88 struct uart_port *__uport = uport; \
90 spin_unlock_irqrestore(&__uport->lock, flags); \
91 uart_port_deref(__uport); \
95 static inline struct uart_port *uart_port_check(struct uart_state *state)
97 lockdep_assert_held(&state->port.mutex);
98 return state->uart_port;
102 * uart_write_wakeup - schedule write processing
103 * @port: port to be processed
105 * This routine is used by the interrupt handler to schedule processing in the
106 * software interrupt portion of the driver. A driver is expected to call this
107 * function when the number of characters in the transmit buffer have dropped
110 * Locking: @port->lock should be held
112 void uart_write_wakeup(struct uart_port *port)
114 struct uart_state *state = port->state;
116 * This means you called this function _after_ the port was
117 * closed. No cookie for you.
120 tty_port_tty_wakeup(&state->port);
122 EXPORT_SYMBOL(uart_write_wakeup);
124 static void uart_stop(struct tty_struct *tty)
126 struct uart_state *state = tty->driver_data;
127 struct uart_port *port;
130 port = uart_port_lock(state, flags);
132 port->ops->stop_tx(port);
133 uart_port_unlock(port, flags);
136 static void __uart_start(struct uart_state *state)
138 struct uart_port *port = state->uart_port;
139 struct serial_port_device *port_dev;
142 if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
145 port_dev = port->port_dev;
147 /* Increment the runtime PM usage count for the active check below */
148 err = pm_runtime_get(&port_dev->dev);
149 if (err < 0 && err != -EINPROGRESS) {
150 pm_runtime_put_noidle(&port_dev->dev);
155 * Start TX if enabled, and kick runtime PM. If the device is not
156 * enabled, serial_port_runtime_resume() calls start_tx() again
157 * after enabling the device.
159 if (!pm_runtime_enabled(port->dev) || pm_runtime_active(port->dev))
160 port->ops->start_tx(port);
161 pm_runtime_mark_last_busy(&port_dev->dev);
162 pm_runtime_put_autosuspend(&port_dev->dev);
165 static void uart_start(struct tty_struct *tty)
167 struct uart_state *state = tty->driver_data;
168 struct uart_port *port;
171 port = uart_port_lock(state, flags);
173 uart_port_unlock(port, flags);
177 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
182 spin_lock_irqsave(&port->lock, flags);
184 port->mctrl = (old & ~clear) | set;
185 if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
186 port->ops->set_mctrl(port, port->mctrl);
187 spin_unlock_irqrestore(&port->lock, flags);
190 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
191 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
193 static void uart_port_dtr_rts(struct uart_port *uport, bool active)
196 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
198 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
201 /* Caller holds port mutex */
202 static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
203 const struct ktermios *old_termios)
205 struct uart_port *uport = uart_port_check(state);
206 struct ktermios *termios;
210 * If we have no tty, termios, or the port does not exist,
211 * then we can't set the parameters for this port.
213 if (!tty || uport->type == PORT_UNKNOWN)
216 termios = &tty->termios;
217 uport->ops->set_termios(uport, termios, old_termios);
220 * Set modem status enables based on termios cflag
222 spin_lock_irq(&uport->lock);
223 if (termios->c_cflag & CRTSCTS)
224 uport->status |= UPSTAT_CTS_ENABLE;
226 uport->status &= ~UPSTAT_CTS_ENABLE;
228 if (termios->c_cflag & CLOCAL)
229 uport->status &= ~UPSTAT_DCD_ENABLE;
231 uport->status |= UPSTAT_DCD_ENABLE;
233 /* reset sw-assisted CTS flow control based on (possibly) new mode */
234 old_hw_stopped = uport->hw_stopped;
235 uport->hw_stopped = uart_softcts_mode(uport) &&
236 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
237 if (uport->hw_stopped != old_hw_stopped) {
239 uport->ops->stop_tx(uport);
243 spin_unlock_irq(&uport->lock);
247 * Startup the port. This will be called once per open. All calls
248 * will be serialised by the per-port mutex.
250 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
253 struct uart_port *uport = uart_port_check(state);
258 if (uport->type == PORT_UNKNOWN)
262 * Make sure the device is in D0 state.
264 uart_change_pm(state, UART_PM_STATE_ON);
267 * Initialise and allocate the transmit and temporary
270 page = get_zeroed_page(GFP_KERNEL);
274 uart_port_lock(state, flags);
275 if (!state->xmit.buf) {
276 state->xmit.buf = (unsigned char *) page;
277 uart_circ_clear(&state->xmit);
278 uart_port_unlock(uport, flags);
280 uart_port_unlock(uport, flags);
282 * Do not free() the page under the port lock, see
288 retval = uport->ops->startup(uport);
290 if (uart_console(uport) && uport->cons->cflag) {
291 tty->termios.c_cflag = uport->cons->cflag;
292 tty->termios.c_ispeed = uport->cons->ispeed;
293 tty->termios.c_ospeed = uport->cons->ospeed;
294 uport->cons->cflag = 0;
295 uport->cons->ispeed = 0;
296 uport->cons->ospeed = 0;
299 * Initialise the hardware port settings.
301 uart_change_line_settings(tty, state, NULL);
304 * Setup the RTS and DTR signals once the
305 * port is open and ready to respond.
307 if (init_hw && C_BAUD(tty))
308 uart_port_dtr_rts(uport, true);
312 * This is to allow setserial on this port. People may want to set
313 * port/irq/type and then reconfigure the port properly if it failed
316 if (retval && capable(CAP_SYS_ADMIN))
322 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
325 struct tty_port *port = &state->port;
328 if (tty_port_initialized(port))
331 retval = uart_port_startup(tty, state, init_hw);
333 set_bit(TTY_IO_ERROR, &tty->flags);
339 * This routine will shutdown a serial port; interrupts are disabled, and
340 * DTR is dropped if the hangup on close termio flag is on. Calls to
341 * uart_shutdown are serialised by the per-port semaphore.
343 * uport == NULL if uart_port has already been removed
345 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
347 struct uart_port *uport = uart_port_check(state);
348 struct tty_port *port = &state->port;
350 char *xmit_buf = NULL;
353 * Set the TTY IO error marker
356 set_bit(TTY_IO_ERROR, &tty->flags);
358 if (tty_port_initialized(port)) {
359 tty_port_set_initialized(port, false);
362 * Turn off DTR and RTS early.
364 if (uport && uart_console(uport) && tty) {
365 uport->cons->cflag = tty->termios.c_cflag;
366 uport->cons->ispeed = tty->termios.c_ispeed;
367 uport->cons->ospeed = tty->termios.c_ospeed;
370 if (!tty || C_HUPCL(tty))
371 uart_port_dtr_rts(uport, false);
373 uart_port_shutdown(port);
377 * It's possible for shutdown to be called after suspend if we get
378 * a DCD drop (hangup) at just the right time. Clear suspended bit so
379 * we don't try to resume a port that has been shutdown.
381 tty_port_set_suspended(port, false);
384 * Do not free() the transmit buffer page under the port lock since
385 * this can create various circular locking scenarios. For instance,
386 * console driver may need to allocate/free a debug object, which
387 * can endup in printk() recursion.
389 uart_port_lock(state, flags);
390 xmit_buf = state->xmit.buf;
391 state->xmit.buf = NULL;
392 uart_port_unlock(uport, flags);
394 free_page((unsigned long)xmit_buf);
398 * uart_update_timeout - update per-port frame timing information
399 * @port: uart_port structure describing the port
400 * @cflag: termios cflag value
401 * @baud: speed of the port
403 * Set the @port frame timing information from which the FIFO timeout value is
404 * derived. The @cflag value should reflect the actual hardware settings as
405 * number of bits, parity, stop bits and baud rate is taken into account here.
407 * Locking: caller is expected to take @port->lock
410 uart_update_timeout(struct uart_port *port, unsigned int cflag,
413 unsigned int size = tty_get_frame_size(cflag);
416 frame_time = (u64)size * NSEC_PER_SEC;
417 port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
419 EXPORT_SYMBOL(uart_update_timeout);
422 * uart_get_baud_rate - return baud rate for a particular port
423 * @port: uart_port structure describing the port in question.
424 * @termios: desired termios settings
425 * @old: old termios (or %NULL)
426 * @min: minimum acceptable baud rate
427 * @max: maximum acceptable baud rate
429 * Decode the termios structure into a numeric baud rate, taking account of the
430 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
433 * If the new baud rate is invalid, try the @old termios setting. If it's still
434 * invalid, we try 9600 baud.
436 * The @termios structure is updated to reflect the baud rate we're actually
437 * going to be using. Don't do this for the case where B0 is requested ("hang
440 * Locking: caller dependent
443 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
444 const struct ktermios *old, unsigned int min, unsigned int max)
448 unsigned int altbaud;
450 upf_t flags = port->flags & UPF_SPD_MASK;
470 for (try = 0; try < 2; try++) {
471 baud = tty_termios_baud_rate(termios);
474 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
477 if (try == 0 && baud == 38400)
481 * Special case: B0 rate.
488 if (baud >= min && baud <= max)
492 * Oops, the quotient was zero. Try again with
493 * the old baud rate if possible.
495 termios->c_cflag &= ~CBAUD;
497 baud = tty_termios_baud_rate(old);
499 tty_termios_encode_baud_rate(termios,
506 * As a last resort, if the range cannot be met then clip to
507 * the nearest chip supported rate.
511 tty_termios_encode_baud_rate(termios,
514 tty_termios_encode_baud_rate(termios,
518 /* Should never happen */
522 EXPORT_SYMBOL(uart_get_baud_rate);
525 * uart_get_divisor - return uart clock divisor
526 * @port: uart_port structure describing the port
527 * @baud: desired baud rate
529 * Calculate the divisor (baud_base / baud) for the specified @baud,
530 * appropriately rounded.
532 * If 38400 baud and custom divisor is selected, return the custom divisor
535 * Locking: caller dependent
538 uart_get_divisor(struct uart_port *port, unsigned int baud)
543 * Old custom speed handling.
545 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
546 quot = port->custom_divisor;
548 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
552 EXPORT_SYMBOL(uart_get_divisor);
554 static int uart_put_char(struct tty_struct *tty, u8 c)
556 struct uart_state *state = tty->driver_data;
557 struct uart_port *port;
558 struct circ_buf *circ;
563 port = uart_port_lock(state, flags);
565 uart_port_unlock(port, flags);
569 if (port && uart_circ_chars_free(circ) != 0) {
570 circ->buf[circ->head] = c;
571 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
574 uart_port_unlock(port, flags);
578 static void uart_flush_chars(struct tty_struct *tty)
583 static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
585 struct uart_state *state = tty->driver_data;
586 struct uart_port *port;
587 struct circ_buf *circ;
592 * This means you called this function _after_ the port was
593 * closed. No cookie for you.
598 port = uart_port_lock(state, flags);
601 uart_port_unlock(port, flags);
606 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
611 memcpy(circ->buf + circ->head, buf, c);
612 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
619 uart_port_unlock(port, flags);
623 static unsigned int uart_write_room(struct tty_struct *tty)
625 struct uart_state *state = tty->driver_data;
626 struct uart_port *port;
630 port = uart_port_lock(state, flags);
631 ret = uart_circ_chars_free(&state->xmit);
632 uart_port_unlock(port, flags);
636 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
638 struct uart_state *state = tty->driver_data;
639 struct uart_port *port;
643 port = uart_port_lock(state, flags);
644 ret = uart_circ_chars_pending(&state->xmit);
645 uart_port_unlock(port, flags);
649 static void uart_flush_buffer(struct tty_struct *tty)
651 struct uart_state *state = tty->driver_data;
652 struct uart_port *port;
656 * This means you called this function _after_ the port was
657 * closed. No cookie for you.
662 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
664 port = uart_port_lock(state, flags);
667 uart_circ_clear(&state->xmit);
668 if (port->ops->flush_buffer)
669 port->ops->flush_buffer(port);
670 uart_port_unlock(port, flags);
671 tty_port_tty_wakeup(&state->port);
675 * This function performs low-level write of high-priority XON/XOFF
676 * character and accounting for it.
678 * Requires uart_port to implement .serial_out().
680 void uart_xchar_out(struct uart_port *uport, int offset)
682 serial_port_out(uport, offset, uport->x_char);
686 EXPORT_SYMBOL_GPL(uart_xchar_out);
689 * This function is used to send a high-priority XON/XOFF character to
692 static void uart_send_xchar(struct tty_struct *tty, char ch)
694 struct uart_state *state = tty->driver_data;
695 struct uart_port *port;
698 port = uart_port_ref(state);
702 if (port->ops->send_xchar)
703 port->ops->send_xchar(port, ch);
705 spin_lock_irqsave(&port->lock, flags);
708 port->ops->start_tx(port);
709 spin_unlock_irqrestore(&port->lock, flags);
711 uart_port_deref(port);
714 static void uart_throttle(struct tty_struct *tty)
716 struct uart_state *state = tty->driver_data;
717 upstat_t mask = UPSTAT_SYNC_FIFO;
718 struct uart_port *port;
720 port = uart_port_ref(state);
725 mask |= UPSTAT_AUTOXOFF;
727 mask |= UPSTAT_AUTORTS;
729 if (port->status & mask) {
730 port->ops->throttle(port);
731 mask &= ~port->status;
734 if (mask & UPSTAT_AUTORTS)
735 uart_clear_mctrl(port, TIOCM_RTS);
737 if (mask & UPSTAT_AUTOXOFF)
738 uart_send_xchar(tty, STOP_CHAR(tty));
740 uart_port_deref(port);
743 static void uart_unthrottle(struct tty_struct *tty)
745 struct uart_state *state = tty->driver_data;
746 upstat_t mask = UPSTAT_SYNC_FIFO;
747 struct uart_port *port;
749 port = uart_port_ref(state);
754 mask |= UPSTAT_AUTOXOFF;
756 mask |= UPSTAT_AUTORTS;
758 if (port->status & mask) {
759 port->ops->unthrottle(port);
760 mask &= ~port->status;
763 if (mask & UPSTAT_AUTORTS)
764 uart_set_mctrl(port, TIOCM_RTS);
766 if (mask & UPSTAT_AUTOXOFF)
767 uart_send_xchar(tty, START_CHAR(tty));
769 uart_port_deref(port);
772 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
774 struct uart_state *state = container_of(port, struct uart_state, port);
775 struct uart_port *uport;
779 * Ensure the state we copy is consistent and no hardware changes
782 mutex_lock(&port->mutex);
783 uport = uart_port_check(state);
787 retinfo->type = uport->type;
788 retinfo->line = uport->line;
789 retinfo->port = uport->iobase;
790 if (HIGH_BITS_OFFSET)
791 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
792 retinfo->irq = uport->irq;
793 retinfo->flags = (__force int)uport->flags;
794 retinfo->xmit_fifo_size = uport->fifosize;
795 retinfo->baud_base = uport->uartclk / 16;
796 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
797 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
798 ASYNC_CLOSING_WAIT_NONE :
799 jiffies_to_msecs(port->closing_wait) / 10;
800 retinfo->custom_divisor = uport->custom_divisor;
801 retinfo->hub6 = uport->hub6;
802 retinfo->io_type = uport->iotype;
803 retinfo->iomem_reg_shift = uport->regshift;
804 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
808 mutex_unlock(&port->mutex);
812 static int uart_get_info_user(struct tty_struct *tty,
813 struct serial_struct *ss)
815 struct uart_state *state = tty->driver_data;
816 struct tty_port *port = &state->port;
818 return uart_get_info(port, ss) < 0 ? -EIO : 0;
821 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
822 struct uart_state *state,
823 struct serial_struct *new_info)
825 struct uart_port *uport = uart_port_check(state);
826 unsigned long new_port;
827 unsigned int change_irq, change_port, closing_wait;
828 unsigned int old_custom_divisor, close_delay;
829 upf_t old_flags, new_flags;
835 new_port = new_info->port;
836 if (HIGH_BITS_OFFSET)
837 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
839 new_info->irq = irq_canonicalize(new_info->irq);
840 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
841 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
842 ASYNC_CLOSING_WAIT_NONE :
843 msecs_to_jiffies(new_info->closing_wait * 10);
846 change_irq = !(uport->flags & UPF_FIXED_PORT)
847 && new_info->irq != uport->irq;
850 * Since changing the 'type' of the port changes its resource
851 * allocations, we should treat type changes the same as
854 change_port = !(uport->flags & UPF_FIXED_PORT)
855 && (new_port != uport->iobase ||
856 (unsigned long)new_info->iomem_base != uport->mapbase ||
857 new_info->hub6 != uport->hub6 ||
858 new_info->io_type != uport->iotype ||
859 new_info->iomem_reg_shift != uport->regshift ||
860 new_info->type != uport->type);
862 old_flags = uport->flags;
863 new_flags = (__force upf_t)new_info->flags;
864 old_custom_divisor = uport->custom_divisor;
866 if (!capable(CAP_SYS_ADMIN)) {
868 if (change_irq || change_port ||
869 (new_info->baud_base != uport->uartclk / 16) ||
870 (close_delay != port->close_delay) ||
871 (closing_wait != port->closing_wait) ||
872 (new_info->xmit_fifo_size &&
873 new_info->xmit_fifo_size != uport->fifosize) ||
874 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
876 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
877 (new_flags & UPF_USR_MASK));
878 uport->custom_divisor = new_info->custom_divisor;
882 if (change_irq || change_port) {
883 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
889 * Ask the low level driver to verify the settings.
891 if (uport->ops->verify_port)
892 retval = uport->ops->verify_port(uport, new_info);
894 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
895 (new_info->baud_base < 9600))
901 if (change_port || change_irq) {
905 * Make sure that we are the sole user of this port.
907 if (tty_port_users(port) > 1)
911 * We need to shutdown the serial port at the old
912 * port/type/irq combination.
914 uart_shutdown(tty, state);
918 unsigned long old_iobase, old_mapbase;
919 unsigned int old_type, old_iotype, old_hub6, old_shift;
921 old_iobase = uport->iobase;
922 old_mapbase = uport->mapbase;
923 old_type = uport->type;
924 old_hub6 = uport->hub6;
925 old_iotype = uport->iotype;
926 old_shift = uport->regshift;
929 * Free and release old regions
931 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
932 uport->ops->release_port(uport);
934 uport->iobase = new_port;
935 uport->type = new_info->type;
936 uport->hub6 = new_info->hub6;
937 uport->iotype = new_info->io_type;
938 uport->regshift = new_info->iomem_reg_shift;
939 uport->mapbase = (unsigned long)new_info->iomem_base;
942 * Claim and map the new regions
944 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
945 retval = uport->ops->request_port(uport);
947 /* Always success - Jean II */
952 * If we fail to request resources for the
953 * new port, try to restore the old settings.
956 uport->iobase = old_iobase;
957 uport->type = old_type;
958 uport->hub6 = old_hub6;
959 uport->iotype = old_iotype;
960 uport->regshift = old_shift;
961 uport->mapbase = old_mapbase;
963 if (old_type != PORT_UNKNOWN) {
964 retval = uport->ops->request_port(uport);
966 * If we failed to restore the old settings,
970 uport->type = PORT_UNKNOWN;
978 /* Added to return the correct error -Ram Gupta */
984 uport->irq = new_info->irq;
985 if (!(uport->flags & UPF_FIXED_PORT))
986 uport->uartclk = new_info->baud_base * 16;
987 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
988 (new_flags & UPF_CHANGE_MASK);
989 uport->custom_divisor = new_info->custom_divisor;
990 port->close_delay = close_delay;
991 port->closing_wait = closing_wait;
992 if (new_info->xmit_fifo_size)
993 uport->fifosize = new_info->xmit_fifo_size;
997 if (uport->type == PORT_UNKNOWN)
999 if (tty_port_initialized(port)) {
1000 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1001 old_custom_divisor != uport->custom_divisor) {
1003 * If they're setting up a custom divisor or speed,
1004 * instead of clearing it, then bitch about it.
1006 if (uport->flags & UPF_SPD_MASK) {
1007 dev_notice_ratelimited(uport->dev,
1008 "%s sets custom speed on %s. This is deprecated.\n",
1010 tty_name(port->tty));
1012 uart_change_line_settings(tty, state, NULL);
1015 retval = uart_startup(tty, state, true);
1017 tty_port_set_initialized(port, true);
1025 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1027 struct uart_state *state = tty->driver_data;
1028 struct tty_port *port = &state->port;
1031 down_write(&tty->termios_rwsem);
1033 * This semaphore protects port->count. It is also
1034 * very useful to prevent opens. Also, take the
1035 * port configuration semaphore to make sure that a
1036 * module insertion/removal doesn't change anything
1039 mutex_lock(&port->mutex);
1040 retval = uart_set_info(tty, port, state, ss);
1041 mutex_unlock(&port->mutex);
1042 up_write(&tty->termios_rwsem);
1047 * uart_get_lsr_info - get line status register info
1048 * @tty: tty associated with the UART
1049 * @state: UART being queried
1050 * @value: returned modem value
1052 static int uart_get_lsr_info(struct tty_struct *tty,
1053 struct uart_state *state, unsigned int __user *value)
1055 struct uart_port *uport = uart_port_check(state);
1056 unsigned int result;
1058 result = uport->ops->tx_empty(uport);
1061 * If we're about to load something into the transmit
1062 * register, we'll pretend the transmitter isn't empty to
1063 * avoid a race condition (depending on when the transmit
1064 * interrupt happens).
1066 if (uport->x_char ||
1067 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1068 !uart_tx_stopped(uport)))
1069 result &= ~TIOCSER_TEMT;
1071 return put_user(result, value);
1074 static int uart_tiocmget(struct tty_struct *tty)
1076 struct uart_state *state = tty->driver_data;
1077 struct tty_port *port = &state->port;
1078 struct uart_port *uport;
1081 mutex_lock(&port->mutex);
1082 uport = uart_port_check(state);
1086 if (!tty_io_error(tty)) {
1087 result = uport->mctrl;
1088 spin_lock_irq(&uport->lock);
1089 result |= uport->ops->get_mctrl(uport);
1090 spin_unlock_irq(&uport->lock);
1093 mutex_unlock(&port->mutex);
1098 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1100 struct uart_state *state = tty->driver_data;
1101 struct tty_port *port = &state->port;
1102 struct uart_port *uport;
1105 mutex_lock(&port->mutex);
1106 uport = uart_port_check(state);
1110 if (!tty_io_error(tty)) {
1111 uart_update_mctrl(uport, set, clear);
1115 mutex_unlock(&port->mutex);
1119 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1121 struct uart_state *state = tty->driver_data;
1122 struct tty_port *port = &state->port;
1123 struct uart_port *uport;
1126 mutex_lock(&port->mutex);
1127 uport = uart_port_check(state);
1131 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1132 uport->ops->break_ctl(uport, break_state);
1135 mutex_unlock(&port->mutex);
1139 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1141 struct tty_port *port = &state->port;
1142 struct uart_port *uport;
1145 if (!capable(CAP_SYS_ADMIN))
1149 * Take the per-port semaphore. This prevents count from
1150 * changing, and hence any extra opens of the port while
1151 * we're auto-configuring.
1153 if (mutex_lock_interruptible(&port->mutex))
1154 return -ERESTARTSYS;
1156 uport = uart_port_check(state);
1163 if (tty_port_users(port) == 1) {
1164 uart_shutdown(tty, state);
1167 * If we already have a port type configured,
1168 * we must release its resources.
1170 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1171 uport->ops->release_port(uport);
1173 flags = UART_CONFIG_TYPE;
1174 if (uport->flags & UPF_AUTO_IRQ)
1175 flags |= UART_CONFIG_IRQ;
1178 * This will claim the ports resources if
1181 uport->ops->config_port(uport, flags);
1183 ret = uart_startup(tty, state, true);
1185 tty_port_set_initialized(port, true);
1190 mutex_unlock(&port->mutex);
1194 static void uart_enable_ms(struct uart_port *uport)
1197 * Force modem status interrupts on
1199 if (uport->ops->enable_ms)
1200 uport->ops->enable_ms(uport);
1204 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1205 * - mask passed in arg for lines of interest
1206 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1207 * Caller should use TIOCGICOUNT to see which one it was
1209 * FIXME: This wants extracting into a common all driver implementation
1210 * of TIOCMWAIT using tty_port.
1212 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1214 struct uart_port *uport;
1215 struct tty_port *port = &state->port;
1216 DECLARE_WAITQUEUE(wait, current);
1217 struct uart_icount cprev, cnow;
1221 * note the counters on entry
1223 uport = uart_port_ref(state);
1226 spin_lock_irq(&uport->lock);
1227 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1228 uart_enable_ms(uport);
1229 spin_unlock_irq(&uport->lock);
1231 add_wait_queue(&port->delta_msr_wait, &wait);
1233 spin_lock_irq(&uport->lock);
1234 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1235 spin_unlock_irq(&uport->lock);
1237 set_current_state(TASK_INTERRUPTIBLE);
1239 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1240 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1241 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1242 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1249 /* see if a signal did it */
1250 if (signal_pending(current)) {
1257 __set_current_state(TASK_RUNNING);
1258 remove_wait_queue(&port->delta_msr_wait, &wait);
1259 uart_port_deref(uport);
1265 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1266 * Return: write counters to the user passed counter struct
1267 * NB: both 1->0 and 0->1 transitions are counted except for
1268 * RI where only 0->1 is counted.
1270 static int uart_get_icount(struct tty_struct *tty,
1271 struct serial_icounter_struct *icount)
1273 struct uart_state *state = tty->driver_data;
1274 struct uart_icount cnow;
1275 struct uart_port *uport;
1277 uport = uart_port_ref(state);
1280 spin_lock_irq(&uport->lock);
1281 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1282 spin_unlock_irq(&uport->lock);
1283 uart_port_deref(uport);
1285 icount->cts = cnow.cts;
1286 icount->dsr = cnow.dsr;
1287 icount->rng = cnow.rng;
1288 icount->dcd = cnow.dcd;
1289 icount->rx = cnow.rx;
1290 icount->tx = cnow.tx;
1291 icount->frame = cnow.frame;
1292 icount->overrun = cnow.overrun;
1293 icount->parity = cnow.parity;
1294 icount->brk = cnow.brk;
1295 icount->buf_overrun = cnow.buf_overrun;
1300 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1301 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1302 SER_RS485_TERMINATE_BUS)
1304 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1306 u32 flags = rs485->flags;
1308 /* Don't return -EINVAL for unsupported legacy flags */
1309 flags &= ~SER_RS485_LEGACY_FLAGS;
1312 * For any bit outside of the legacy ones that is not supported by
1313 * the driver, return -EINVAL.
1315 if (flags & ~port->rs485_supported.flags)
1318 /* Asking for address w/o addressing mode? */
1319 if (!(rs485->flags & SER_RS485_ADDRB) &&
1320 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1323 /* Address given but not enabled? */
1324 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1326 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1332 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1333 struct serial_rs485 *rs485)
1335 if (!port->rs485_supported.delay_rts_before_send) {
1336 if (rs485->delay_rts_before_send) {
1337 dev_warn_ratelimited(port->dev,
1338 "%s (%d): RTS delay before sending not supported\n",
1339 port->name, port->line);
1341 rs485->delay_rts_before_send = 0;
1342 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1343 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1344 dev_warn_ratelimited(port->dev,
1345 "%s (%d): RTS delay before sending clamped to %u ms\n",
1346 port->name, port->line, rs485->delay_rts_before_send);
1349 if (!port->rs485_supported.delay_rts_after_send) {
1350 if (rs485->delay_rts_after_send) {
1351 dev_warn_ratelimited(port->dev,
1352 "%s (%d): RTS delay after sending not supported\n",
1353 port->name, port->line);
1355 rs485->delay_rts_after_send = 0;
1356 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1357 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1358 dev_warn_ratelimited(port->dev,
1359 "%s (%d): RTS delay after sending clamped to %u ms\n",
1360 port->name, port->line, rs485->delay_rts_after_send);
1364 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1366 u32 supported_flags = port->rs485_supported.flags;
1368 if (!(rs485->flags & SER_RS485_ENABLED)) {
1369 memset(rs485, 0, sizeof(*rs485));
1373 rs485->flags &= supported_flags;
1375 /* Pick sane settings if the user hasn't */
1376 if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1377 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1378 if (supported_flags & SER_RS485_RTS_ON_SEND) {
1379 rs485->flags |= SER_RS485_RTS_ON_SEND;
1380 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1382 dev_warn_ratelimited(port->dev,
1383 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1384 port->name, port->line);
1386 rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1387 rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1389 dev_warn_ratelimited(port->dev,
1390 "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1391 port->name, port->line);
1395 uart_sanitize_serial_rs485_delays(port, rs485);
1397 /* Return clean padding area to userspace */
1398 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1399 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1402 static void uart_set_rs485_termination(struct uart_port *port,
1403 const struct serial_rs485 *rs485)
1405 if (!(rs485->flags & SER_RS485_ENABLED))
1408 gpiod_set_value_cansleep(port->rs485_term_gpio,
1409 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1412 static int uart_rs485_config(struct uart_port *port)
1414 struct serial_rs485 *rs485 = &port->rs485;
1415 unsigned long flags;
1418 if (!(rs485->flags & SER_RS485_ENABLED))
1421 uart_sanitize_serial_rs485(port, rs485);
1422 uart_set_rs485_termination(port, rs485);
1424 spin_lock_irqsave(&port->lock, flags);
1425 ret = port->rs485_config(port, NULL, rs485);
1426 spin_unlock_irqrestore(&port->lock, flags);
1428 memset(rs485, 0, sizeof(*rs485));
1433 static int uart_get_rs485_config(struct uart_port *port,
1434 struct serial_rs485 __user *rs485)
1436 unsigned long flags;
1437 struct serial_rs485 aux;
1439 spin_lock_irqsave(&port->lock, flags);
1441 spin_unlock_irqrestore(&port->lock, flags);
1443 if (copy_to_user(rs485, &aux, sizeof(aux)))
1449 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1450 struct serial_rs485 __user *rs485_user)
1452 struct serial_rs485 rs485;
1454 unsigned long flags;
1456 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1459 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1462 ret = uart_check_rs485_flags(port, &rs485);
1465 uart_sanitize_serial_rs485(port, &rs485);
1466 uart_set_rs485_termination(port, &rs485);
1468 spin_lock_irqsave(&port->lock, flags);
1469 ret = port->rs485_config(port, &tty->termios, &rs485);
1471 port->rs485 = rs485;
1473 /* Reset RTS and other mctrl lines when disabling RS485 */
1474 if (!(rs485.flags & SER_RS485_ENABLED))
1475 port->ops->set_mctrl(port, port->mctrl);
1477 spin_unlock_irqrestore(&port->lock, flags);
1481 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1487 static int uart_get_iso7816_config(struct uart_port *port,
1488 struct serial_iso7816 __user *iso7816)
1490 unsigned long flags;
1491 struct serial_iso7816 aux;
1493 if (!port->iso7816_config)
1496 spin_lock_irqsave(&port->lock, flags);
1497 aux = port->iso7816;
1498 spin_unlock_irqrestore(&port->lock, flags);
1500 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1506 static int uart_set_iso7816_config(struct uart_port *port,
1507 struct serial_iso7816 __user *iso7816_user)
1509 struct serial_iso7816 iso7816;
1511 unsigned long flags;
1513 if (!port->iso7816_config)
1516 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1520 * There are 5 words reserved for future use. Check that userspace
1521 * doesn't put stuff in there to prevent breakages in the future.
1523 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1524 if (iso7816.reserved[i])
1527 spin_lock_irqsave(&port->lock, flags);
1528 ret = port->iso7816_config(port, &iso7816);
1529 spin_unlock_irqrestore(&port->lock, flags);
1533 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1540 * Called via sys_ioctl. We can use spin_lock_irq() here.
1543 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1545 struct uart_state *state = tty->driver_data;
1546 struct tty_port *port = &state->port;
1547 struct uart_port *uport;
1548 void __user *uarg = (void __user *)arg;
1549 int ret = -ENOIOCTLCMD;
1553 * These ioctls don't rely on the hardware to be present.
1557 down_write(&tty->termios_rwsem);
1558 ret = uart_do_autoconfig(tty, state);
1559 up_write(&tty->termios_rwsem);
1563 if (ret != -ENOIOCTLCMD)
1566 if (tty_io_error(tty)) {
1572 * The following should only be used when hardware is present.
1576 ret = uart_wait_modem_status(state, arg);
1580 if (ret != -ENOIOCTLCMD)
1583 /* rs485_config requires more locking than others */
1584 if (cmd == TIOCSRS485)
1585 down_write(&tty->termios_rwsem);
1587 mutex_lock(&port->mutex);
1588 uport = uart_port_check(state);
1590 if (!uport || tty_io_error(tty)) {
1596 * All these rely on hardware being present and need to be
1597 * protected against the tty being hung up.
1601 case TIOCSERGETLSR: /* Get line status register */
1602 ret = uart_get_lsr_info(tty, state, uarg);
1606 ret = uart_get_rs485_config(uport, uarg);
1610 ret = uart_set_rs485_config(tty, uport, uarg);
1614 ret = uart_set_iso7816_config(state->uart_port, uarg);
1618 ret = uart_get_iso7816_config(state->uart_port, uarg);
1621 if (uport->ops->ioctl)
1622 ret = uport->ops->ioctl(uport, cmd, arg);
1626 mutex_unlock(&port->mutex);
1627 if (cmd == TIOCSRS485)
1628 up_write(&tty->termios_rwsem);
1633 static void uart_set_ldisc(struct tty_struct *tty)
1635 struct uart_state *state = tty->driver_data;
1636 struct uart_port *uport;
1637 struct tty_port *port = &state->port;
1639 if (!tty_port_initialized(port))
1642 mutex_lock(&state->port.mutex);
1643 uport = uart_port_check(state);
1644 if (uport && uport->ops->set_ldisc)
1645 uport->ops->set_ldisc(uport, &tty->termios);
1646 mutex_unlock(&state->port.mutex);
1649 static void uart_set_termios(struct tty_struct *tty,
1650 const struct ktermios *old_termios)
1652 struct uart_state *state = tty->driver_data;
1653 struct uart_port *uport;
1654 unsigned int cflag = tty->termios.c_cflag;
1655 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1656 bool sw_changed = false;
1658 mutex_lock(&state->port.mutex);
1659 uport = uart_port_check(state);
1664 * Drivers doing software flow control also need to know
1665 * about changes to these input settings.
1667 if (uport->flags & UPF_SOFT_FLOW) {
1668 iflag_mask |= IXANY|IXON|IXOFF;
1670 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1671 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1675 * These are the bits that are used to setup various
1676 * flags in the low level driver. We can ignore the Bfoo
1677 * bits in c_cflag; c_[io]speed will always be set
1678 * appropriately by set_termios() in tty_ioctl.c
1680 if ((cflag ^ old_termios->c_cflag) == 0 &&
1681 tty->termios.c_ospeed == old_termios->c_ospeed &&
1682 tty->termios.c_ispeed == old_termios->c_ispeed &&
1683 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1688 uart_change_line_settings(tty, state, old_termios);
1689 /* reload cflag from termios; port driver may have overridden flags */
1690 cflag = tty->termios.c_cflag;
1692 /* Handle transition to B0 status */
1693 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1694 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1695 /* Handle transition away from B0 status */
1696 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1697 unsigned int mask = TIOCM_DTR;
1699 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1701 uart_set_mctrl(uport, mask);
1704 mutex_unlock(&state->port.mutex);
1708 * Calls to uart_close() are serialised via the tty_lock in
1709 * drivers/tty/tty_io.c:tty_release()
1710 * drivers/tty/tty_io.c:do_tty_hangup()
1712 static void uart_close(struct tty_struct *tty, struct file *filp)
1714 struct uart_state *state = tty->driver_data;
1717 struct uart_driver *drv = tty->driver->driver_state;
1718 struct tty_port *port;
1720 state = drv->state + tty->index;
1721 port = &state->port;
1722 spin_lock_irq(&port->lock);
1724 spin_unlock_irq(&port->lock);
1728 pr_debug("uart_close(%d) called\n", tty->index);
1730 tty_port_close(tty->port, tty, filp);
1733 static void uart_tty_port_shutdown(struct tty_port *port)
1735 struct uart_state *state = container_of(port, struct uart_state, port);
1736 struct uart_port *uport = uart_port_check(state);
1740 * At this point, we stop accepting input. To do this, we
1741 * disable the receive line status interrupts.
1743 if (WARN(!uport, "detached port still initialized!\n"))
1746 spin_lock_irq(&uport->lock);
1747 uport->ops->stop_rx(uport);
1748 spin_unlock_irq(&uport->lock);
1750 uart_port_shutdown(port);
1753 * It's possible for shutdown to be called after suspend if we get
1754 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1755 * we don't try to resume a port that has been shutdown.
1757 tty_port_set_suspended(port, false);
1760 * Free the transmit buffer.
1762 spin_lock_irq(&uport->lock);
1763 buf = state->xmit.buf;
1764 state->xmit.buf = NULL;
1765 spin_unlock_irq(&uport->lock);
1767 free_page((unsigned long)buf);
1769 uart_change_pm(state, UART_PM_STATE_OFF);
1772 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1774 struct uart_state *state = tty->driver_data;
1775 struct uart_port *port;
1776 unsigned long char_time, expire, fifo_timeout;
1778 port = uart_port_ref(state);
1782 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1783 uart_port_deref(port);
1788 * Set the check interval to be 1/5 of the estimated time to
1789 * send a single character, and make it at least 1. The check
1790 * interval should also be less than the timeout.
1792 * Note: we have to use pretty tight timings here to satisfy
1795 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1797 if (timeout && timeout < char_time)
1798 char_time = timeout;
1800 if (!uart_cts_enabled(port)) {
1802 * If the transmitter hasn't cleared in twice the approximate
1803 * amount of time to send the entire FIFO, it probably won't
1804 * ever clear. This assumes the UART isn't doing flow
1805 * control, which is currently the case. Hence, if it ever
1806 * takes longer than FIFO timeout, this is probably due to a
1807 * UART bug of some kind. So, we clamp the timeout parameter at
1810 fifo_timeout = uart_fifo_timeout(port);
1811 if (timeout == 0 || timeout > 2 * fifo_timeout)
1812 timeout = 2 * fifo_timeout;
1815 expire = jiffies + timeout;
1817 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1818 port->line, jiffies, expire);
1821 * Check whether the transmitter is empty every 'char_time'.
1822 * 'timeout' / 'expire' give us the maximum amount of time
1825 while (!port->ops->tx_empty(port)) {
1826 msleep_interruptible(jiffies_to_msecs(char_time));
1827 if (signal_pending(current))
1829 if (timeout && time_after(jiffies, expire))
1832 uart_port_deref(port);
1836 * Calls to uart_hangup() are serialised by the tty_lock in
1837 * drivers/tty/tty_io.c:do_tty_hangup()
1838 * This runs from a workqueue and can sleep for a _short_ time only.
1840 static void uart_hangup(struct tty_struct *tty)
1842 struct uart_state *state = tty->driver_data;
1843 struct tty_port *port = &state->port;
1844 struct uart_port *uport;
1845 unsigned long flags;
1847 pr_debug("uart_hangup(%d)\n", tty->index);
1849 mutex_lock(&port->mutex);
1850 uport = uart_port_check(state);
1851 WARN(!uport, "hangup of detached port!\n");
1853 if (tty_port_active(port)) {
1854 uart_flush_buffer(tty);
1855 uart_shutdown(tty, state);
1856 spin_lock_irqsave(&port->lock, flags);
1858 spin_unlock_irqrestore(&port->lock, flags);
1859 tty_port_set_active(port, false);
1860 tty_port_tty_set(port, NULL);
1861 if (uport && !uart_console(uport))
1862 uart_change_pm(state, UART_PM_STATE_OFF);
1863 wake_up_interruptible(&port->open_wait);
1864 wake_up_interruptible(&port->delta_msr_wait);
1866 mutex_unlock(&port->mutex);
1869 /* uport == NULL if uart_port has already been removed */
1870 static void uart_port_shutdown(struct tty_port *port)
1872 struct uart_state *state = container_of(port, struct uart_state, port);
1873 struct uart_port *uport = uart_port_check(state);
1876 * clear delta_msr_wait queue to avoid mem leaks: we may free
1877 * the irq here so the queue might never be woken up. Note
1878 * that we won't end up waiting on delta_msr_wait again since
1879 * any outstanding file descriptors should be pointing at
1880 * hung_up_tty_fops now.
1882 wake_up_interruptible(&port->delta_msr_wait);
1885 /* Free the IRQ and disable the port. */
1886 uport->ops->shutdown(uport);
1888 /* Ensure that the IRQ handler isn't running on another CPU. */
1889 synchronize_irq(uport->irq);
1893 static bool uart_carrier_raised(struct tty_port *port)
1895 struct uart_state *state = container_of(port, struct uart_state, port);
1896 struct uart_port *uport;
1899 uport = uart_port_ref(state);
1901 * Should never observe uport == NULL since checks for hangup should
1902 * abort the tty_port_block_til_ready() loop before checking for carrier
1903 * raised -- but report carrier raised if it does anyway so open will
1904 * continue and not sleep
1906 if (WARN_ON(!uport))
1908 spin_lock_irq(&uport->lock);
1909 uart_enable_ms(uport);
1910 mctrl = uport->ops->get_mctrl(uport);
1911 spin_unlock_irq(&uport->lock);
1912 uart_port_deref(uport);
1914 return mctrl & TIOCM_CAR;
1917 static void uart_dtr_rts(struct tty_port *port, bool active)
1919 struct uart_state *state = container_of(port, struct uart_state, port);
1920 struct uart_port *uport;
1922 uport = uart_port_ref(state);
1925 uart_port_dtr_rts(uport, active);
1926 uart_port_deref(uport);
1929 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1931 struct uart_driver *drv = driver->driver_state;
1932 struct uart_state *state = drv->state + tty->index;
1934 tty->driver_data = state;
1936 return tty_standard_install(driver, tty);
1940 * Calls to uart_open are serialised by the tty_lock in
1941 * drivers/tty/tty_io.c:tty_open()
1942 * Note that if this fails, then uart_close() _will_ be called.
1944 * In time, we want to scrap the "opening nonpresent ports"
1945 * behaviour and implement an alternative way for setserial
1946 * to set base addresses/ports/types. This will allow us to
1947 * get rid of a certain amount of extra tests.
1949 static int uart_open(struct tty_struct *tty, struct file *filp)
1951 struct uart_state *state = tty->driver_data;
1954 retval = tty_port_open(&state->port, tty, filp);
1961 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1963 struct uart_state *state = container_of(port, struct uart_state, port);
1964 struct uart_port *uport;
1967 uport = uart_port_check(state);
1968 if (!uport || uport->flags & UPF_DEAD)
1972 * Start up the serial port.
1974 ret = uart_startup(tty, state, false);
1976 tty_port_set_active(port, true);
1981 static const char *uart_type(struct uart_port *port)
1983 const char *str = NULL;
1985 if (port->ops->type)
1986 str = port->ops->type(port);
1994 #ifdef CONFIG_PROC_FS
1996 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1998 struct uart_state *state = drv->state + i;
1999 struct tty_port *port = &state->port;
2000 enum uart_pm_state pm_state;
2001 struct uart_port *uport;
2003 unsigned int status;
2006 mutex_lock(&port->mutex);
2007 uport = uart_port_check(state);
2011 mmio = uport->iotype >= UPIO_MEM;
2012 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2013 uport->line, uart_type(uport),
2014 mmio ? "mmio:0x" : "port:",
2015 mmio ? (unsigned long long)uport->mapbase
2016 : (unsigned long long)uport->iobase,
2019 if (uport->type == PORT_UNKNOWN) {
2024 if (capable(CAP_SYS_ADMIN)) {
2025 pm_state = state->pm_state;
2026 if (pm_state != UART_PM_STATE_ON)
2027 uart_change_pm(state, UART_PM_STATE_ON);
2028 spin_lock_irq(&uport->lock);
2029 status = uport->ops->get_mctrl(uport);
2030 spin_unlock_irq(&uport->lock);
2031 if (pm_state != UART_PM_STATE_ON)
2032 uart_change_pm(state, pm_state);
2034 seq_printf(m, " tx:%d rx:%d",
2035 uport->icount.tx, uport->icount.rx);
2036 if (uport->icount.frame)
2037 seq_printf(m, " fe:%d", uport->icount.frame);
2038 if (uport->icount.parity)
2039 seq_printf(m, " pe:%d", uport->icount.parity);
2040 if (uport->icount.brk)
2041 seq_printf(m, " brk:%d", uport->icount.brk);
2042 if (uport->icount.overrun)
2043 seq_printf(m, " oe:%d", uport->icount.overrun);
2044 if (uport->icount.buf_overrun)
2045 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2047 #define INFOBIT(bit, str) \
2048 if (uport->mctrl & (bit)) \
2049 strncat(stat_buf, (str), sizeof(stat_buf) - \
2050 strlen(stat_buf) - 2)
2051 #define STATBIT(bit, str) \
2052 if (status & (bit)) \
2053 strncat(stat_buf, (str), sizeof(stat_buf) - \
2054 strlen(stat_buf) - 2)
2058 INFOBIT(TIOCM_RTS, "|RTS");
2059 STATBIT(TIOCM_CTS, "|CTS");
2060 INFOBIT(TIOCM_DTR, "|DTR");
2061 STATBIT(TIOCM_DSR, "|DSR");
2062 STATBIT(TIOCM_CAR, "|CD");
2063 STATBIT(TIOCM_RNG, "|RI");
2067 seq_puts(m, stat_buf);
2073 mutex_unlock(&port->mutex);
2076 static int uart_proc_show(struct seq_file *m, void *v)
2078 struct tty_driver *ttydrv = m->private;
2079 struct uart_driver *drv = ttydrv->driver_state;
2082 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2083 for (i = 0; i < drv->nr; i++)
2084 uart_line_info(m, drv, i);
2089 static void uart_port_spin_lock_init(struct uart_port *port)
2091 spin_lock_init(&port->lock);
2092 lockdep_set_class(&port->lock, &port_lock_key);
2095 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2097 * uart_console_write - write a console message to a serial port
2098 * @port: the port to write the message
2099 * @s: array of characters
2100 * @count: number of characters in string to write
2101 * @putchar: function to write character to port
2103 void uart_console_write(struct uart_port *port, const char *s,
2105 void (*putchar)(struct uart_port *, unsigned char))
2109 for (i = 0; i < count; i++, s++) {
2111 putchar(port, '\r');
2115 EXPORT_SYMBOL_GPL(uart_console_write);
2118 * uart_get_console - get uart port for console
2119 * @ports: ports to search in
2120 * @nr: number of @ports
2121 * @co: console to search for
2122 * Returns: uart_port for the console @co
2124 * Check whether an invalid uart number has been specified (as @co->index), and
2125 * if so, search for the first available port that does have console support.
2127 struct uart_port * __init
2128 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2130 int idx = co->index;
2132 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2133 ports[idx].membase == NULL))
2134 for (idx = 0; idx < nr; idx++)
2135 if (ports[idx].iobase != 0 ||
2136 ports[idx].membase != NULL)
2145 * uart_parse_earlycon - Parse earlycon options
2146 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2147 * @iotype: ptr for decoded iotype (out)
2148 * @addr: ptr for decoded mapbase/iobase (out)
2149 * @options: ptr for <options> field; %NULL if not present (out)
2151 * Decodes earlycon kernel command line parameters of the form:
2152 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2153 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2155 * The optional form:
2156 * * earlycon=<name>,0x<addr>,<options>
2157 * * console=<name>,0x<addr>,<options>
2159 * is also accepted; the returned @iotype will be %UPIO_MEM.
2161 * Returns: 0 on success or -%EINVAL on failure
2163 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2166 if (strncmp(p, "mmio,", 5) == 0) {
2169 } else if (strncmp(p, "mmio16,", 7) == 0) {
2170 *iotype = UPIO_MEM16;
2172 } else if (strncmp(p, "mmio32,", 7) == 0) {
2173 *iotype = UPIO_MEM32;
2175 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2176 *iotype = UPIO_MEM32BE;
2178 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2179 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2180 UPIO_MEM32BE : UPIO_MEM32;
2182 } else if (strncmp(p, "io,", 3) == 0) {
2183 *iotype = UPIO_PORT;
2185 } else if (strncmp(p, "0x", 2) == 0) {
2192 * Before you replace it with kstrtoull(), think about options separator
2193 * (',') it will not tolerate
2195 *addr = simple_strtoull(p, NULL, 0);
2203 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2206 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2207 * @options: pointer to option string
2208 * @baud: pointer to an 'int' variable for the baud rate.
2209 * @parity: pointer to an 'int' variable for the parity.
2210 * @bits: pointer to an 'int' variable for the number of data bits.
2211 * @flow: pointer to an 'int' variable for the flow control character.
2213 * uart_parse_options() decodes a string containing the serial console
2214 * options. The format of the string is <baud><parity><bits><flow>,
2218 uart_parse_options(const char *options, int *baud, int *parity,
2219 int *bits, int *flow)
2221 const char *s = options;
2223 *baud = simple_strtoul(s, NULL, 10);
2224 while (*s >= '0' && *s <= '9')
2233 EXPORT_SYMBOL_GPL(uart_parse_options);
2236 * uart_set_options - setup the serial console parameters
2237 * @port: pointer to the serial ports uart_port structure
2238 * @co: console pointer
2240 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2241 * @bits: number of data bits
2242 * @flow: flow control character - 'r' (rts)
2244 * Locking: Caller must hold console_list_lock in order to serialize
2245 * early initialization of the serial-console lock.
2248 uart_set_options(struct uart_port *port, struct console *co,
2249 int baud, int parity, int bits, int flow)
2251 struct ktermios termios;
2252 static struct ktermios dummy;
2255 * Ensure that the serial-console lock is initialised early.
2257 * Note that the console-registered check is needed because
2258 * kgdboc can call uart_set_options() for an already registered
2259 * console via tty_find_polling_driver() and uart_poll_init().
2261 if (!uart_console_registered_locked(port) && !port->console_reinit)
2262 uart_port_spin_lock_init(port);
2264 memset(&termios, 0, sizeof(struct ktermios));
2266 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2267 tty_termios_encode_baud_rate(&termios, baud, baud);
2270 termios.c_cflag |= CS7;
2272 termios.c_cflag |= CS8;
2276 termios.c_cflag |= PARODD;
2279 termios.c_cflag |= PARENB;
2284 termios.c_cflag |= CRTSCTS;
2287 * some uarts on other side don't support no flow control.
2288 * So we set * DTR in host uart to make them happy
2290 port->mctrl |= TIOCM_DTR;
2292 port->ops->set_termios(port, &termios, &dummy);
2294 * Allow the setting of the UART parameters with a NULL console
2298 co->cflag = termios.c_cflag;
2299 co->ispeed = termios.c_ispeed;
2300 co->ospeed = termios.c_ospeed;
2305 EXPORT_SYMBOL_GPL(uart_set_options);
2306 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2309 * uart_change_pm - set power state of the port
2311 * @state: port descriptor
2312 * @pm_state: new state
2314 * Locking: port->mutex has to be held
2316 static void uart_change_pm(struct uart_state *state,
2317 enum uart_pm_state pm_state)
2319 struct uart_port *port = uart_port_check(state);
2321 if (state->pm_state != pm_state) {
2322 if (port && port->ops->pm)
2323 port->ops->pm(port, pm_state, state->pm_state);
2324 state->pm_state = pm_state;
2329 struct uart_port *port;
2330 struct uart_driver *driver;
2333 static int serial_match_port(struct device *dev, void *data)
2335 struct uart_match *match = data;
2336 struct tty_driver *tty_drv = match->driver->tty_driver;
2337 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2340 return dev->devt == devt; /* Actually, only one tty per port */
2343 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2345 struct uart_state *state = drv->state + uport->line;
2346 struct tty_port *port = &state->port;
2347 struct device *tty_dev;
2348 struct uart_match match = {uport, drv};
2350 mutex_lock(&port->mutex);
2352 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2353 if (tty_dev && device_may_wakeup(tty_dev)) {
2354 enable_irq_wake(uport->irq);
2355 put_device(tty_dev);
2356 mutex_unlock(&port->mutex);
2359 put_device(tty_dev);
2362 * Nothing to do if the console is not suspending
2363 * except stop_rx to prevent any asynchronous data
2364 * over RX line. However ensure that we will be
2365 * able to Re-start_rx later.
2367 if (!console_suspend_enabled && uart_console(uport)) {
2368 if (uport->ops->start_rx) {
2369 spin_lock_irq(&uport->lock);
2370 uport->ops->stop_rx(uport);
2371 spin_unlock_irq(&uport->lock);
2376 uport->suspended = 1;
2378 if (tty_port_initialized(port)) {
2379 const struct uart_ops *ops = uport->ops;
2383 tty_port_set_suspended(port, true);
2384 tty_port_set_initialized(port, false);
2386 spin_lock_irq(&uport->lock);
2387 ops->stop_tx(uport);
2388 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2389 ops->set_mctrl(uport, 0);
2390 /* save mctrl so it can be restored on resume */
2391 mctrl = uport->mctrl;
2393 ops->stop_rx(uport);
2394 spin_unlock_irq(&uport->lock);
2397 * Wait for the transmitter to empty.
2399 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2402 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2405 ops->shutdown(uport);
2406 uport->mctrl = mctrl;
2410 * Disable the console device before suspending.
2412 if (uart_console(uport))
2413 console_stop(uport->cons);
2415 uart_change_pm(state, UART_PM_STATE_OFF);
2417 mutex_unlock(&port->mutex);
2421 EXPORT_SYMBOL(uart_suspend_port);
2423 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2425 struct uart_state *state = drv->state + uport->line;
2426 struct tty_port *port = &state->port;
2427 struct device *tty_dev;
2428 struct uart_match match = {uport, drv};
2429 struct ktermios termios;
2431 mutex_lock(&port->mutex);
2433 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2434 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2435 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2436 disable_irq_wake(uport->irq);
2437 put_device(tty_dev);
2438 mutex_unlock(&port->mutex);
2441 put_device(tty_dev);
2442 uport->suspended = 0;
2445 * Re-enable the console device after suspending.
2447 if (uart_console(uport)) {
2449 * First try to use the console cflag setting.
2451 memset(&termios, 0, sizeof(struct ktermios));
2452 termios.c_cflag = uport->cons->cflag;
2453 termios.c_ispeed = uport->cons->ispeed;
2454 termios.c_ospeed = uport->cons->ospeed;
2457 * If that's unset, use the tty termios setting.
2459 if (port->tty && termios.c_cflag == 0)
2460 termios = port->tty->termios;
2462 if (console_suspend_enabled)
2463 uart_change_pm(state, UART_PM_STATE_ON);
2464 uport->ops->set_termios(uport, &termios, NULL);
2465 if (!console_suspend_enabled && uport->ops->start_rx) {
2466 spin_lock_irq(&uport->lock);
2467 uport->ops->start_rx(uport);
2468 spin_unlock_irq(&uport->lock);
2470 if (console_suspend_enabled)
2471 console_start(uport->cons);
2474 if (tty_port_suspended(port)) {
2475 const struct uart_ops *ops = uport->ops;
2478 uart_change_pm(state, UART_PM_STATE_ON);
2479 spin_lock_irq(&uport->lock);
2480 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2481 ops->set_mctrl(uport, 0);
2482 spin_unlock_irq(&uport->lock);
2483 if (console_suspend_enabled || !uart_console(uport)) {
2484 /* Protected by port mutex for now */
2485 struct tty_struct *tty = port->tty;
2487 ret = ops->startup(uport);
2490 uart_change_line_settings(tty, state, NULL);
2491 uart_rs485_config(uport);
2492 spin_lock_irq(&uport->lock);
2493 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2494 ops->set_mctrl(uport, uport->mctrl);
2495 ops->start_tx(uport);
2496 spin_unlock_irq(&uport->lock);
2497 tty_port_set_initialized(port, true);
2500 * Failed to resume - maybe hardware went away?
2501 * Clear the "initialized" flag so we won't try
2502 * to call the low level drivers shutdown method.
2504 uart_shutdown(tty, state);
2508 tty_port_set_suspended(port, false);
2511 mutex_unlock(&port->mutex);
2515 EXPORT_SYMBOL(uart_resume_port);
2518 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2522 switch (port->iotype) {
2524 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2527 snprintf(address, sizeof(address),
2528 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2536 snprintf(address, sizeof(address),
2537 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2540 strscpy(address, "*unknown*", sizeof(address));
2544 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2545 port->dev ? dev_name(port->dev) : "",
2546 port->dev ? ": " : "",
2548 address, port->irq, port->uartclk / 16, uart_type(port));
2550 /* The magic multiplier feature is a bit obscure, so report it too. */
2551 if (port->flags & UPF_MAGIC_MULTIPLIER)
2552 pr_info("%s%s%s extra baud rates supported: %d, %d",
2553 port->dev ? dev_name(port->dev) : "",
2554 port->dev ? ": " : "",
2556 port->uartclk / 8, port->uartclk / 4);
2560 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2561 struct uart_port *port)
2566 * If there isn't a port here, don't do anything further.
2568 if (!port->iobase && !port->mapbase && !port->membase)
2572 * Now do the auto configuration stuff. Note that config_port
2573 * is expected to claim the resources and map the port for us.
2576 if (port->flags & UPF_AUTO_IRQ)
2577 flags |= UART_CONFIG_IRQ;
2578 if (port->flags & UPF_BOOT_AUTOCONF) {
2579 if (!(port->flags & UPF_FIXED_TYPE)) {
2580 port->type = PORT_UNKNOWN;
2581 flags |= UART_CONFIG_TYPE;
2583 port->ops->config_port(port, flags);
2586 if (port->type != PORT_UNKNOWN) {
2587 unsigned long flags;
2589 uart_report_port(drv, port);
2591 /* Power up port for set_mctrl() */
2592 uart_change_pm(state, UART_PM_STATE_ON);
2595 * Ensure that the modem control lines are de-activated.
2596 * keep the DTR setting that is set in uart_set_options()
2597 * We probably don't need a spinlock around this, but
2599 spin_lock_irqsave(&port->lock, flags);
2600 port->mctrl &= TIOCM_DTR;
2601 if (!(port->rs485.flags & SER_RS485_ENABLED))
2602 port->ops->set_mctrl(port, port->mctrl);
2603 spin_unlock_irqrestore(&port->lock, flags);
2605 uart_rs485_config(port);
2608 * If this driver supports console, and it hasn't been
2609 * successfully registered yet, try to re-register it.
2610 * It may be that the port was not available.
2612 if (port->cons && !console_is_registered(port->cons))
2613 register_console(port->cons);
2616 * Power down all ports by default, except the
2617 * console if we have one.
2619 if (!uart_console(port))
2620 uart_change_pm(state, UART_PM_STATE_OFF);
2624 #ifdef CONFIG_CONSOLE_POLL
2626 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2628 struct uart_driver *drv = driver->driver_state;
2629 struct uart_state *state = drv->state + line;
2630 enum uart_pm_state pm_state;
2631 struct tty_port *tport;
2632 struct uart_port *port;
2639 tport = &state->port;
2640 mutex_lock(&tport->mutex);
2642 port = uart_port_check(state);
2643 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2648 pm_state = state->pm_state;
2649 uart_change_pm(state, UART_PM_STATE_ON);
2651 if (port->ops->poll_init) {
2653 * We don't set initialized as we only initialized the hw,
2654 * e.g. state->xmit is still uninitialized.
2656 if (!tty_port_initialized(tport))
2657 ret = port->ops->poll_init(port);
2660 if (!ret && options) {
2661 uart_parse_options(options, &baud, &parity, &bits, &flow);
2662 console_list_lock();
2663 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2664 console_list_unlock();
2668 uart_change_pm(state, pm_state);
2669 mutex_unlock(&tport->mutex);
2673 static int uart_poll_get_char(struct tty_driver *driver, int line)
2675 struct uart_driver *drv = driver->driver_state;
2676 struct uart_state *state = drv->state + line;
2677 struct uart_port *port;
2680 port = uart_port_ref(state);
2682 ret = port->ops->poll_get_char(port);
2683 uart_port_deref(port);
2689 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2691 struct uart_driver *drv = driver->driver_state;
2692 struct uart_state *state = drv->state + line;
2693 struct uart_port *port;
2695 port = uart_port_ref(state);
2700 port->ops->poll_put_char(port, '\r');
2701 port->ops->poll_put_char(port, ch);
2702 uart_port_deref(port);
2706 static const struct tty_operations uart_ops = {
2707 .install = uart_install,
2709 .close = uart_close,
2710 .write = uart_write,
2711 .put_char = uart_put_char,
2712 .flush_chars = uart_flush_chars,
2713 .write_room = uart_write_room,
2714 .chars_in_buffer= uart_chars_in_buffer,
2715 .flush_buffer = uart_flush_buffer,
2716 .ioctl = uart_ioctl,
2717 .throttle = uart_throttle,
2718 .unthrottle = uart_unthrottle,
2719 .send_xchar = uart_send_xchar,
2720 .set_termios = uart_set_termios,
2721 .set_ldisc = uart_set_ldisc,
2723 .start = uart_start,
2724 .hangup = uart_hangup,
2725 .break_ctl = uart_break_ctl,
2726 .wait_until_sent= uart_wait_until_sent,
2727 #ifdef CONFIG_PROC_FS
2728 .proc_show = uart_proc_show,
2730 .tiocmget = uart_tiocmget,
2731 .tiocmset = uart_tiocmset,
2732 .set_serial = uart_set_info_user,
2733 .get_serial = uart_get_info_user,
2734 .get_icount = uart_get_icount,
2735 #ifdef CONFIG_CONSOLE_POLL
2736 .poll_init = uart_poll_init,
2737 .poll_get_char = uart_poll_get_char,
2738 .poll_put_char = uart_poll_put_char,
2742 static const struct tty_port_operations uart_port_ops = {
2743 .carrier_raised = uart_carrier_raised,
2744 .dtr_rts = uart_dtr_rts,
2745 .activate = uart_port_activate,
2746 .shutdown = uart_tty_port_shutdown,
2750 * uart_register_driver - register a driver with the uart core layer
2751 * @drv: low level driver structure
2753 * Register a uart driver with the core driver. We in turn register with the
2754 * tty layer, and initialise the core driver per-port state.
2756 * We have a proc file in /proc/tty/driver which is named after the normal
2759 * @drv->port should be %NULL, and the per-port structures should be registered
2760 * using uart_add_one_port() after this call has succeeded.
2762 * Locking: none, Interrupts: enabled
2764 int uart_register_driver(struct uart_driver *drv)
2766 struct tty_driver *normal;
2767 int i, retval = -ENOMEM;
2772 * Maybe we should be using a slab cache for this, especially if
2773 * we have a large number of ports to handle.
2775 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2779 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2780 TTY_DRIVER_DYNAMIC_DEV);
2781 if (IS_ERR(normal)) {
2782 retval = PTR_ERR(normal);
2786 drv->tty_driver = normal;
2788 normal->driver_name = drv->driver_name;
2789 normal->name = drv->dev_name;
2790 normal->major = drv->major;
2791 normal->minor_start = drv->minor;
2792 normal->type = TTY_DRIVER_TYPE_SERIAL;
2793 normal->subtype = SERIAL_TYPE_NORMAL;
2794 normal->init_termios = tty_std_termios;
2795 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2796 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2797 normal->driver_state = drv;
2798 tty_set_operations(normal, &uart_ops);
2801 * Initialise the UART state(s).
2803 for (i = 0; i < drv->nr; i++) {
2804 struct uart_state *state = drv->state + i;
2805 struct tty_port *port = &state->port;
2807 tty_port_init(port);
2808 port->ops = &uart_port_ops;
2811 retval = tty_register_driver(normal);
2815 for (i = 0; i < drv->nr; i++)
2816 tty_port_destroy(&drv->state[i].port);
2817 tty_driver_kref_put(normal);
2823 EXPORT_SYMBOL(uart_register_driver);
2826 * uart_unregister_driver - remove a driver from the uart core layer
2827 * @drv: low level driver structure
2829 * Remove all references to a driver from the core driver. The low level
2830 * driver must have removed all its ports via the uart_remove_one_port() if it
2831 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2833 * Locking: none, Interrupts: enabled
2835 void uart_unregister_driver(struct uart_driver *drv)
2837 struct tty_driver *p = drv->tty_driver;
2840 tty_unregister_driver(p);
2841 tty_driver_kref_put(p);
2842 for (i = 0; i < drv->nr; i++)
2843 tty_port_destroy(&drv->state[i].port);
2846 drv->tty_driver = NULL;
2848 EXPORT_SYMBOL(uart_unregister_driver);
2850 struct tty_driver *uart_console_device(struct console *co, int *index)
2852 struct uart_driver *p = co->data;
2854 return p->tty_driver;
2856 EXPORT_SYMBOL_GPL(uart_console_device);
2858 static ssize_t uartclk_show(struct device *dev,
2859 struct device_attribute *attr, char *buf)
2861 struct serial_struct tmp;
2862 struct tty_port *port = dev_get_drvdata(dev);
2864 uart_get_info(port, &tmp);
2865 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2868 static ssize_t type_show(struct device *dev,
2869 struct device_attribute *attr, char *buf)
2871 struct serial_struct tmp;
2872 struct tty_port *port = dev_get_drvdata(dev);
2874 uart_get_info(port, &tmp);
2875 return sprintf(buf, "%d\n", tmp.type);
2878 static ssize_t line_show(struct device *dev,
2879 struct device_attribute *attr, char *buf)
2881 struct serial_struct tmp;
2882 struct tty_port *port = dev_get_drvdata(dev);
2884 uart_get_info(port, &tmp);
2885 return sprintf(buf, "%d\n", tmp.line);
2888 static ssize_t port_show(struct device *dev,
2889 struct device_attribute *attr, char *buf)
2891 struct serial_struct tmp;
2892 struct tty_port *port = dev_get_drvdata(dev);
2893 unsigned long ioaddr;
2895 uart_get_info(port, &tmp);
2897 if (HIGH_BITS_OFFSET)
2898 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2899 return sprintf(buf, "0x%lX\n", ioaddr);
2902 static ssize_t irq_show(struct device *dev,
2903 struct device_attribute *attr, char *buf)
2905 struct serial_struct tmp;
2906 struct tty_port *port = dev_get_drvdata(dev);
2908 uart_get_info(port, &tmp);
2909 return sprintf(buf, "%d\n", tmp.irq);
2912 static ssize_t flags_show(struct device *dev,
2913 struct device_attribute *attr, char *buf)
2915 struct serial_struct tmp;
2916 struct tty_port *port = dev_get_drvdata(dev);
2918 uart_get_info(port, &tmp);
2919 return sprintf(buf, "0x%X\n", tmp.flags);
2922 static ssize_t xmit_fifo_size_show(struct device *dev,
2923 struct device_attribute *attr, char *buf)
2925 struct serial_struct tmp;
2926 struct tty_port *port = dev_get_drvdata(dev);
2928 uart_get_info(port, &tmp);
2929 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2932 static ssize_t close_delay_show(struct device *dev,
2933 struct device_attribute *attr, char *buf)
2935 struct serial_struct tmp;
2936 struct tty_port *port = dev_get_drvdata(dev);
2938 uart_get_info(port, &tmp);
2939 return sprintf(buf, "%d\n", tmp.close_delay);
2942 static ssize_t closing_wait_show(struct device *dev,
2943 struct device_attribute *attr, char *buf)
2945 struct serial_struct tmp;
2946 struct tty_port *port = dev_get_drvdata(dev);
2948 uart_get_info(port, &tmp);
2949 return sprintf(buf, "%d\n", tmp.closing_wait);
2952 static ssize_t custom_divisor_show(struct device *dev,
2953 struct device_attribute *attr, char *buf)
2955 struct serial_struct tmp;
2956 struct tty_port *port = dev_get_drvdata(dev);
2958 uart_get_info(port, &tmp);
2959 return sprintf(buf, "%d\n", tmp.custom_divisor);
2962 static ssize_t io_type_show(struct device *dev,
2963 struct device_attribute *attr, char *buf)
2965 struct serial_struct tmp;
2966 struct tty_port *port = dev_get_drvdata(dev);
2968 uart_get_info(port, &tmp);
2969 return sprintf(buf, "%d\n", tmp.io_type);
2972 static ssize_t iomem_base_show(struct device *dev,
2973 struct device_attribute *attr, char *buf)
2975 struct serial_struct tmp;
2976 struct tty_port *port = dev_get_drvdata(dev);
2978 uart_get_info(port, &tmp);
2979 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2982 static ssize_t iomem_reg_shift_show(struct device *dev,
2983 struct device_attribute *attr, char *buf)
2985 struct serial_struct tmp;
2986 struct tty_port *port = dev_get_drvdata(dev);
2988 uart_get_info(port, &tmp);
2989 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2992 static ssize_t console_show(struct device *dev,
2993 struct device_attribute *attr, char *buf)
2995 struct tty_port *port = dev_get_drvdata(dev);
2996 struct uart_state *state = container_of(port, struct uart_state, port);
2997 struct uart_port *uport;
2998 bool console = false;
3000 mutex_lock(&port->mutex);
3001 uport = uart_port_check(state);
3003 console = uart_console_registered(uport);
3004 mutex_unlock(&port->mutex);
3006 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3009 static ssize_t console_store(struct device *dev,
3010 struct device_attribute *attr, const char *buf, size_t count)
3012 struct tty_port *port = dev_get_drvdata(dev);
3013 struct uart_state *state = container_of(port, struct uart_state, port);
3014 struct uart_port *uport;
3015 bool oldconsole, newconsole;
3018 ret = kstrtobool(buf, &newconsole);
3022 mutex_lock(&port->mutex);
3023 uport = uart_port_check(state);
3025 oldconsole = uart_console_registered(uport);
3026 if (oldconsole && !newconsole) {
3027 ret = unregister_console(uport->cons);
3028 } else if (!oldconsole && newconsole) {
3029 if (uart_console(uport)) {
3030 uport->console_reinit = 1;
3031 register_console(uport->cons);
3039 mutex_unlock(&port->mutex);
3041 return ret < 0 ? ret : count;
3044 static DEVICE_ATTR_RO(uartclk);
3045 static DEVICE_ATTR_RO(type);
3046 static DEVICE_ATTR_RO(line);
3047 static DEVICE_ATTR_RO(port);
3048 static DEVICE_ATTR_RO(irq);
3049 static DEVICE_ATTR_RO(flags);
3050 static DEVICE_ATTR_RO(xmit_fifo_size);
3051 static DEVICE_ATTR_RO(close_delay);
3052 static DEVICE_ATTR_RO(closing_wait);
3053 static DEVICE_ATTR_RO(custom_divisor);
3054 static DEVICE_ATTR_RO(io_type);
3055 static DEVICE_ATTR_RO(iomem_base);
3056 static DEVICE_ATTR_RO(iomem_reg_shift);
3057 static DEVICE_ATTR_RW(console);
3059 static struct attribute *tty_dev_attrs[] = {
3060 &dev_attr_uartclk.attr,
3061 &dev_attr_type.attr,
3062 &dev_attr_line.attr,
3063 &dev_attr_port.attr,
3065 &dev_attr_flags.attr,
3066 &dev_attr_xmit_fifo_size.attr,
3067 &dev_attr_close_delay.attr,
3068 &dev_attr_closing_wait.attr,
3069 &dev_attr_custom_divisor.attr,
3070 &dev_attr_io_type.attr,
3071 &dev_attr_iomem_base.attr,
3072 &dev_attr_iomem_reg_shift.attr,
3073 &dev_attr_console.attr,
3077 static const struct attribute_group tty_dev_attr_group = {
3078 .attrs = tty_dev_attrs,
3082 * serial_core_add_one_port - attach a driver-defined port structure
3083 * @drv: pointer to the uart low level driver structure for this port
3084 * @uport: uart port structure to use for this port.
3086 * Context: task context, might sleep
3088 * This allows the driver @drv to register its own uart_port structure with the
3089 * core driver. The main purpose is to allow the low level uart drivers to
3090 * expand uart_port, rather than having yet more levels of structures.
3091 * Caller must hold port_mutex.
3093 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3095 struct uart_state *state;
3096 struct tty_port *port;
3098 struct device *tty_dev;
3101 if (uport->line >= drv->nr)
3104 state = drv->state + uport->line;
3105 port = &state->port;
3107 mutex_lock(&port->mutex);
3108 if (state->uart_port) {
3113 /* Link the port to the driver state table and vice versa */
3114 atomic_set(&state->refcount, 1);
3115 init_waitqueue_head(&state->remove_wait);
3116 state->uart_port = uport;
3117 uport->state = state;
3119 state->pm_state = UART_PM_STATE_UNDEFINED;
3120 uport->cons = drv->cons;
3121 uport->minor = drv->tty_driver->minor_start + uport->line;
3122 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3123 drv->tty_driver->name_base + uport->line);
3130 * If this port is in use as a console then the spinlock is already
3133 if (!uart_console_registered(uport))
3134 uart_port_spin_lock_init(uport);
3136 if (uport->cons && uport->dev)
3137 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3139 tty_port_link_device(port, drv->tty_driver, uport->line);
3140 uart_configure_port(drv, state, uport);
3142 port->console = uart_console(uport);
3145 if (uport->attr_group)
3148 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3150 if (!uport->tty_groups) {
3154 uport->tty_groups[0] = &tty_dev_attr_group;
3155 if (uport->attr_group)
3156 uport->tty_groups[1] = uport->attr_group;
3159 * Register the port whether it's detected or not. This allows
3160 * setserial to be used to alter this port's parameters.
3162 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3163 uport->line, uport->dev, port, uport->tty_groups);
3164 if (!IS_ERR(tty_dev)) {
3165 device_set_wakeup_capable(tty_dev, 1);
3167 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3172 mutex_unlock(&port->mutex);
3178 * serial_core_remove_one_port - detach a driver defined port structure
3179 * @drv: pointer to the uart low level driver structure for this port
3180 * @uport: uart port structure for this port
3182 * Context: task context, might sleep
3184 * This unhooks (and hangs up) the specified port structure from the core
3185 * driver. No further calls will be made to the low-level code for this port.
3186 * Caller must hold port_mutex.
3188 static void serial_core_remove_one_port(struct uart_driver *drv,
3189 struct uart_port *uport)
3191 struct uart_state *state = drv->state + uport->line;
3192 struct tty_port *port = &state->port;
3193 struct uart_port *uart_port;
3194 struct tty_struct *tty;
3196 mutex_lock(&port->mutex);
3197 uart_port = uart_port_check(state);
3198 if (uart_port != uport)
3199 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3203 mutex_unlock(&port->mutex);
3206 mutex_unlock(&port->mutex);
3209 * Remove the devices from the tty layer
3211 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3213 tty = tty_port_tty_get(port);
3215 tty_vhangup(port->tty);
3220 * If the port is used as a console, unregister it
3222 if (uart_console(uport))
3223 unregister_console(uport->cons);
3226 * Free the port IO and memory resources, if any.
3228 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3229 uport->ops->release_port(uport);
3230 kfree(uport->tty_groups);
3234 * Indicate that there isn't a port here anymore.
3236 uport->type = PORT_UNKNOWN;
3237 uport->port_dev = NULL;
3239 mutex_lock(&port->mutex);
3240 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3241 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3242 state->uart_port = NULL;
3243 mutex_unlock(&port->mutex);
3247 * uart_match_port - are the two ports equivalent?
3248 * @port1: first port
3249 * @port2: second port
3251 * This utility function can be used to determine whether two uart_port
3252 * structures describe the same port.
3254 bool uart_match_port(const struct uart_port *port1,
3255 const struct uart_port *port2)
3257 if (port1->iotype != port2->iotype)
3260 switch (port1->iotype) {
3262 return port1->iobase == port2->iobase;
3264 return port1->iobase == port2->iobase &&
3265 port1->hub6 == port2->hub6;
3272 return port1->mapbase == port2->mapbase;
3277 EXPORT_SYMBOL(uart_match_port);
3279 static struct serial_ctrl_device *
3280 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3282 struct device *dev = &port_dev->dev;
3284 return to_serial_base_ctrl_device(dev->parent);
3288 * Find a registered serial core controller device if one exists. Returns
3289 * the first device matching the ctrl_id. Caller must hold port_mutex.
3291 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3292 struct device *phys_dev,
3295 struct uart_state *state;
3298 lockdep_assert_held(&port_mutex);
3300 for (i = 0; i < drv->nr; i++) {
3301 state = drv->state + i;
3302 if (!state->uart_port || !state->uart_port->port_dev)
3305 if (state->uart_port->dev == phys_dev &&
3306 state->uart_port->ctrl_id == ctrl_id)
3307 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3313 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3315 return serial_base_ctrl_add(port, port->dev);
3318 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3319 struct uart_port *port)
3321 struct serial_port_device *port_dev;
3323 port_dev = serial_base_port_add(port, ctrl_dev);
3324 if (IS_ERR(port_dev))
3325 return PTR_ERR(port_dev);
3327 port->port_dev = port_dev;
3333 * Initialize a serial core port device, and a controller device if needed.
3335 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3337 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3340 mutex_lock(&port_mutex);
3343 * Prevent serial_port_runtime_resume() from trying to use the port
3344 * until serial_core_add_one_port() has completed
3346 port->flags |= UPF_DEAD;
3348 /* Inititalize a serial core controller device if needed */
3349 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3351 new_ctrl_dev = serial_core_ctrl_device_add(port);
3352 if (IS_ERR(new_ctrl_dev)) {
3353 ret = PTR_ERR(new_ctrl_dev);
3356 ctrl_dev = new_ctrl_dev;
3360 * Initialize a serial core port device. Tag the port dead to prevent
3361 * serial_port_runtime_resume() trying to do anything until port has
3362 * been registered. It gets cleared by serial_core_add_one_port().
3364 ret = serial_core_port_device_add(ctrl_dev, port);
3366 goto err_unregister_ctrl_dev;
3368 ret = serial_core_add_one_port(drv, port);
3370 goto err_unregister_port_dev;
3372 port->flags &= ~UPF_DEAD;
3374 mutex_unlock(&port_mutex);
3378 err_unregister_port_dev:
3379 serial_base_port_device_remove(port->port_dev);
3381 err_unregister_ctrl_dev:
3382 serial_base_ctrl_device_remove(new_ctrl_dev);
3385 mutex_unlock(&port_mutex);
3391 * Removes a serial core port device, and the related serial core controller
3392 * device if the last instance.
3394 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3396 struct device *phys_dev = port->dev;
3397 struct serial_port_device *port_dev = port->port_dev;
3398 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3399 int ctrl_id = port->ctrl_id;
3401 mutex_lock(&port_mutex);
3403 port->flags |= UPF_DEAD;
3405 serial_core_remove_one_port(drv, port);
3407 /* Note that struct uart_port *port is no longer valid at this point */
3408 serial_base_port_device_remove(port_dev);
3410 /* Drop the serial core controller device if no ports are using it */
3411 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3412 serial_base_ctrl_device_remove(ctrl_dev);
3414 mutex_unlock(&port_mutex);
3418 * uart_handle_dcd_change - handle a change of carrier detect state
3419 * @uport: uart_port structure for the open port
3420 * @active: new carrier detect status
3422 * Caller must hold uport->lock.
3424 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3426 struct tty_port *port = &uport->state->port;
3427 struct tty_struct *tty = port->tty;
3428 struct tty_ldisc *ld;
3430 lockdep_assert_held_once(&uport->lock);
3433 ld = tty_ldisc_ref(tty);
3435 if (ld->ops->dcd_change)
3436 ld->ops->dcd_change(tty, active);
3437 tty_ldisc_deref(ld);
3441 uport->icount.dcd++;
3443 if (uart_dcd_enabled(uport)) {
3445 wake_up_interruptible(&port->open_wait);
3450 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3453 * uart_handle_cts_change - handle a change of clear-to-send state
3454 * @uport: uart_port structure for the open port
3455 * @active: new clear-to-send status
3457 * Caller must hold uport->lock.
3459 void uart_handle_cts_change(struct uart_port *uport, bool active)
3461 lockdep_assert_held_once(&uport->lock);
3463 uport->icount.cts++;
3465 if (uart_softcts_mode(uport)) {
3466 if (uport->hw_stopped) {
3468 uport->hw_stopped = false;
3469 uport->ops->start_tx(uport);
3470 uart_write_wakeup(uport);
3474 uport->hw_stopped = true;
3475 uport->ops->stop_tx(uport);
3481 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3484 * uart_insert_char - push a char to the uart layer
3486 * User is responsible to call tty_flip_buffer_push when they are done with
3489 * @port: corresponding port
3490 * @status: state of the serial port RX buffer (LSR for 8250)
3491 * @overrun: mask of overrun bits in @status
3492 * @ch: character to push
3493 * @flag: flag for the character (see TTY_NORMAL and friends)
3495 void uart_insert_char(struct uart_port *port, unsigned int status,
3496 unsigned int overrun, u8 ch, u8 flag)
3498 struct tty_port *tport = &port->state->port;
3500 if ((status & port->ignore_status_mask & ~overrun) == 0)
3501 if (tty_insert_flip_char(tport, ch, flag) == 0)
3502 ++port->icount.buf_overrun;
3505 * Overrun is special. Since it's reported immediately,
3506 * it doesn't affect the current character.
3508 if (status & ~port->ignore_status_mask & overrun)
3509 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3510 ++port->icount.buf_overrun;
3512 EXPORT_SYMBOL_GPL(uart_insert_char);
3514 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3515 static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3517 static void uart_sysrq_on(struct work_struct *w)
3519 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3521 sysrq_toggle_support(1);
3522 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3523 sysrq_toggle_seq_len, sysrq_toggle_seq);
3525 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3528 * uart_try_toggle_sysrq - Enables SysRq from serial line
3529 * @port: uart_port structure where char(s) after BREAK met
3530 * @ch: new character in the sequence after received BREAK
3532 * Enables magic SysRq when the required sequence is met on port
3533 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3535 * Returns: %false if @ch is out of enabling sequence and should be
3536 * handled some other way, %true if @ch was consumed.
3538 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3540 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3542 if (!sysrq_toggle_seq_len)
3545 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3546 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3547 port->sysrq_seq = 0;
3551 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3552 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3556 schedule_work(&sysrq_enable_work);
3561 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3565 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3566 * @port: uart device's target port
3568 * This function implements the device tree binding described in
3569 * Documentation/devicetree/bindings/serial/rs485.txt.
3571 int uart_get_rs485_mode(struct uart_port *port)
3573 struct serial_rs485 *rs485conf = &port->rs485;
3574 struct device *dev = port->dev;
3577 int rx_during_tx_gpio_flag;
3579 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3582 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3585 rs485conf->delay_rts_before_send = rs485_delay[0];
3586 rs485conf->delay_rts_after_send = rs485_delay[1];
3588 rs485conf->delay_rts_before_send = 0;
3589 rs485conf->delay_rts_after_send = 0;
3592 uart_sanitize_serial_rs485_delays(port, rs485conf);
3595 * Clear full-duplex and enabled flags, set RTS polarity to active high
3596 * to get to a defined state with the following properties:
3598 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3599 SER_RS485_TERMINATE_BUS |
3600 SER_RS485_RTS_AFTER_SEND);
3601 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3603 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3604 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3606 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3607 rs485conf->flags |= SER_RS485_ENABLED;
3609 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3610 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3611 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3615 * Disabling termination by default is the safe choice: Else if many
3616 * bus participants enable it, no communication is possible at all.
3617 * Works fine for short cables and users may enable for longer cables.
3619 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3621 if (IS_ERR(port->rs485_term_gpio)) {
3622 ret = PTR_ERR(port->rs485_term_gpio);
3623 port->rs485_term_gpio = NULL;
3624 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3626 if (port->rs485_term_gpio)
3627 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3629 rx_during_tx_gpio_flag = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3630 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3631 port->rs485_rx_during_tx_gpio = devm_gpiod_get_optional(dev,
3632 "rs485-rx-during-tx",
3633 rx_during_tx_gpio_flag);
3634 if (IS_ERR(port->rs485_rx_during_tx_gpio)) {
3635 ret = PTR_ERR(port->rs485_rx_during_tx_gpio);
3636 port->rs485_rx_during_tx_gpio = NULL;
3637 return dev_err_probe(dev, ret, "Cannot get rs485-rx-during-tx-gpios\n");
3642 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3644 /* Compile-time assertions for serial_rs485 layout */
3645 static_assert(offsetof(struct serial_rs485, padding) ==
3646 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3647 static_assert(offsetof(struct serial_rs485, padding1) ==
3648 offsetof(struct serial_rs485, padding[1]));
3649 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3650 sizeof(struct serial_rs485));
3652 MODULE_DESCRIPTION("Serial driver core");
3653 MODULE_LICENSE("GPL");